About what a Faraday cage is

In the distant 1836, an English scientist, Michael Faraday, conducted a very curious and cognitive experience. According to his instructions, a large wooden cage was pasted with sheets of tin paper (staniola). Then it was isolated from the earth's surface and heavily charged by an electric machine. The potential difference between this design and the ground was so strong that sparks flew from its outer surface as the bodies connected to the earth's surface approached it. Not surprisingly, Faraday caged Faraday's cage to many eyewitnesses. The English physicist himself was inside his design, holding in his hands a very sensitive electroscope.

What made it possible to find out the Faraday cage?

During the test, the fully serviceable device showed the physicist complete absence of electric charge. And this means that such a construction can be effectively used as a shielding shield. Later it was possible to find out that the ability of such a screen to neutralize electromagnetic radiation depends largely on the thickness of its material, the depth of the surface effect and the ratio of the dimensions of the openings with the length of the acting waves. Thus, Faraday's experiments allowed people to find a way to protect sensitive equipment and human health from the harmful effects of a powerful electromagnetic field. This property has received wide application in practice, and it is difficult to imagine what would happen to humanity, if not for the ingenuity and courage of the brave physicist.

How does the Faraday cage work?

When a closed electrically conductive shell enters an electric field, it begins to act on free electrons, as a result of which the opposite sides of such a construction acquire charges, which in turn create a field that completely compensates for the external action. It should be noted that the Faraday cage can only protect from the electric field. A magnetic field, provided that it is static, freely penetrates inside. Therefore, the compass inside this structure will work correctly. In the case of a dynamic electric field, the next thing happens: it creates a dynamic magnetic field, which, according to the laws of physics, generates its own changing electric field, which prevents the creation of a magnetic field inside such a screen.

Modern Faraday cells

Currently, the phenomenon discovered by an English physicist is used for radio cabinets, shielded rooms, RF boxes. Such premises are widely used wherever one needs to protect a person from an electric field. As an electrically conductive material, a fine metal mesh or perforated steel sheets are now commonly used, and the structures themselves are necessarily grounded to dissipate any electrical currents that may appear from external radiation.
In addition, the Faraday cage is widely used for all sorts of tests of computer equipment, electronic components, etc. There are even special individual shielding kits, and some companies offer to shield their people for greater security.